Hello connor39   Palpitations, like the ones you are experiencing, are caused by abnormal electrical conduction in the heart, leading to an irregular and/or too-fast heart rate.  However, due to heart disease, genetics (especially if you have a family history of palpitations) and some other common causes, these pathways do not keep your heart-rate constant.    Though it seems like these occurrences resolve on their own, part of the concern is that the irregular rhythm will not return to a normal rate.  When your heart pumps too fast, it does not allow for adequate filling of the heart with blood and therefore your heart cannot pump enough blood to your vital organs.  This is especially a concern if you have heart disease or risk factors for heart disease.       Some common and less serious causes of palpitations include too much caffeine, found in coffee, teas, and chocolates.  Also, an overactive thyroid gland can cause palpitations.  There are quite rare conditions that can cause palpitations.  However, only a doctor who can order tests for you like an EKG, thyroid stimulating hormone levels (TSH), blood electrolytes, and hemoglobin/hematocrit levels can tell you definitively what is causing your symptoms.    You should make an appointment with your physician soon to discuss your heart!      To your health, Neil, MD